Statistics - market size, number of workers in an occupation, etc. - are vital to knowing how a business figures in its industry. These sites help you put a finger on the right numbers.
Biz stats. This site promises to help you "benchmark a business in five seconds." We didn't set a timer, but it did provide some quick calculations meant to help determine how a business in a given industry - say, construction, accounting, or even a dentist's office - ought to be performing, based on its revenue. Links provide such information as the number of people employed in an industry, and its total U.S. market, in dollars. One interesting comparison: Vehicle manufacturing is a $276-billion-per-year endeavor, but car parts is almost as huge at $237 billion.